CN118017650A

CN118017650A - Charge state prompting circuit and electronic equipment

Info

Publication number: CN118017650A
Application number: CN202410204808.5A
Authority: CN
Inventors: 王韡
Original assignee: Wuhan Xingji Meizu Technology Co ltd
Current assignee: Wuhan Xingji Meizu Technology Co ltd
Priority date: 2024-02-23
Filing date: 2024-02-23
Publication date: 2024-05-10

Abstract

The embodiment of the disclosure provides a charging state prompt circuit and electronic equipment. The charge state prompting circuit includes: the first control branch circuit is configured to control the first node to be coupled with the input voltage terminal based on a charging normal signal output by the charging state terminal so as to provide a first preset voltage for the first node; the second control branch circuit is configured to control the second node to be coupled with the input voltage end under the condition that the first node is a first preset voltage and the positive voltage of the battery is not more than a cut-off voltage, so as to provide the second preset voltage for the second node, and the cut-off voltage is the minimum voltage which can be started by the electronic equipment using the battery; the prompting element is configured to generate preset prompting information under a second preset voltage of the second node. According to the technical scheme, when the electronic equipment is charged after overdischarge, the user can be prompted under the condition that the electronic equipment cannot be started but is charged normally, and the judgment of the user is facilitated.

Description

Charge state prompting circuit and electronic equipment

Technical Field

The disclosure relates to the field of electronic technology, and in particular, to a charging state prompting circuit and an electronic device.

Background

Currently, mobile electronic devices such as mobile phones and tablet computers generally employ rechargeable batteries. The battery is discharged during use or when the electronic device is idle for a period of time, and when the battery is too low, the battery needs to be charged.

When the battery is not overdischarged, the battery is charged, and the electronic equipment can be normally started. When the battery is overdischarged, the battery voltage is lower than the minimum voltage required for the electronic device to be started, namely the cut-off voltage. When the battery is charged after overdischarge, the charging IC charges the battery with a small current in the charging process, and the battery takes a long time to reach the cut-off voltage due to the small current. The electronic equipment can not be started for a long time, and at this time, because the electronic equipment can not be started, a user can not judge whether the electronic equipment is in a normal charging state or a damaged state, and the user is bothered.

Disclosure of Invention

As a first aspect of the embodiments of the present disclosure, the embodiments of the present disclosure provide a charge state prompting circuit, including:

The first control branch circuit is respectively coupled with the charging state end, the reference voltage end, the input voltage end and the first node of the charging chip and is configured to control the first node to be coupled with the input voltage end based on a charging normal signal output by the charging state end so as to provide a first preset voltage for the first node;

The second control branch circuit is respectively coupled with the first node, the anode of the battery, the input voltage end and the second node, and is configured to control the second node to be coupled with the input voltage end so as to provide a second preset voltage for the second node under the condition that the first node is a first preset voltage and the anode voltage of the battery is not more than a cut-off voltage, and the cut-off voltage is the minimum voltage which can be started by using the electronic equipment of the battery;

The prompting element is coupled with the second node and the first reference ground respectively and is configured to generate preset prompting information under a second preset voltage of the second node.

In some embodiments, the second control branch circuit includes:

the first switch branch circuit is respectively coupled with the first node, the positive electrode of the battery and the third node and is configured to be conducted under the condition that the first node is a first preset voltage and the positive electrode voltage of the battery is not greater than a cut-off voltage, so that the third node is coupled with the positive electrode of the battery;

And a second switch branch circuit coupled to the third node, the input voltage terminal, and the second node, respectively, and configured to be turned on when the third node is coupled to the positive electrode of the battery, so that the second node is coupled to the input voltage terminal.

In some embodiments, the first switching branch circuit is turned off and the second switching branch circuit is turned off, and the second node is disconnected from the input voltage terminal, in the case that the positive voltage of the battery is greater than the off voltage.

In some embodiments, the second switch branch circuit includes a first MOS transistor, a gate of the first MOS transistor is coupled to the third node, a first pole of the first MOS transistor is coupled to the input voltage terminal, and a second pole of the first MOS transistor is coupled to the second node.

In some embodiments, a first resistor element is connected between the gate and the first pole of the first MOS transistor, where the first resistor element is configured to make the gate and the first pole of the first MOS transistor have the same potential when the first switch branch circuit is turned off.

In some embodiments, a difference between the voltage of the third node and the voltage of the first pole of the first MOS transistor is less than a threshold voltage of the first MOS transistor.

In some embodiments, the first switching subcircuit includes a first transistor having a base coupled to the first node, an emitter coupled to the positive electrode of the battery, and a collector coupled to the third node;

the first preset voltage is equal to the sum of the cut-off voltage and the threshold voltage of the first triode, wherein the threshold voltage of the first triode is the minimum voltage between the base electrode and the emitter electrode for conducting the first triode.

In some embodiments, the first control branch circuit includes:

The third switch branch circuit is respectively coupled with the charging state end, the reference voltage end and the fourth node of the charging chip and is configured to be conducted under the condition that the charging state end outputs a charging normal signal so that the fourth node is coupled with the reference voltage end;

The fourth switch branch circuit is coupled with the fourth node, the input voltage terminal and the first node respectively and is configured to be conducted under the condition that the fourth node is coupled with the reference voltage terminal, so that the first node is coupled with the input voltage terminal.

In some embodiments, a second resistive element is connected between the input voltage terminal and the fourth switching branch circuit, the first node and the third reference ground are connected with a third resistive element, and in the case that the first switching branch circuit includes a first triode and the first node is coupled to a base of the first triode, the following relationship is satisfied:

wherein V1 is the voltage of the input voltage terminal, vb is the voltage of the base electrode of the first triode, R2 is the resistance value of the second resistor element, R3 is the resistance value of the third resistor element, and Vb is the sum of the cut-off voltage and the threshold voltage of the first triode.

In some embodiments, the fourth switching branch circuit includes a second MOS transistor, a gate of the second MOS transistor is coupled to the fourth node, a first pole of the second MOS transistor is coupled to the input voltage terminal, and a second pole of the second MOS transistor is coupled to the first node.

In some embodiments, a fourth resistance element is connected between the gate and the first pole of the second MOS transistor, and the fourth resistance element is configured to make the gate and the first pole of the second MOS transistor have the same potential when the third switch branch circuit is turned off.

In some embodiments, the third switching subcircuit includes a second transistor having a base coupled to a charge state terminal of the charging chip, an emitter coupled to a reference voltage terminal, and a collector coupled to a fourth node.

In some embodiments, the charge state terminal outputs a charge abnormality signal when the battery is in an abnormal charge state, and the first node is disconnected from the input voltage terminal based on the charge abnormality signal.

As a second aspect of embodiments of the present disclosure, embodiments of the present disclosure provide an electronic device including a charging chip, a battery, and a state of charge indicator circuit in any of the embodiments of the present disclosure.

The foregoing summary is for the purpose of the specification only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present disclosure will become apparent by reference to the drawings and the following detailed description.

Drawings

In the drawings, the same reference numerals refer to the same or similar parts or elements throughout the several views unless otherwise specified. The figures are not necessarily drawn to scale. It is appreciated that these drawings depict only some embodiments according to the disclosure and are not to be considered limiting of its scope.

FIG. 1 is a schematic diagram of a charge status indicator circuit according to an embodiment of the disclosure;

FIG. 2 is a schematic diagram of a state of charge indicator circuit according to another embodiment of the disclosure;

fig. 3 is a schematic diagram of a charge status indicator circuit according to another embodiment of the disclosure.

Detailed Description

Hereinafter, only certain exemplary embodiments are briefly described. As will be recognized by those of skill in the pertinent art, the described embodiments may be modified in various different ways without departing from the spirit or scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

The MOS transistors employed in all embodiments of the present disclosure may be thin film transistors or field effect transistors or other devices having the same characteristics. For a MOS transistor, the source (source electrode, e.g., s-pole in fig. 2) is referred to as a first pole, the drain (drain electrode, e.g., d-pole in fig. 2) is referred to as a second pole, or the drain may be referred to as a first pole, and the source as a second pole. In the embodiment of the disclosure, the corresponding relation between the source electrode and the drain electrode and the first electrode and the second electrode can be judged according to the connection relation of the MOS tube. The MOS tube of the embodiment of the disclosure may adopt a PMOS or an NMOS, the PMOS is turned on when the grid (for example, g pole in fig. 2) is at a low level, and turned off when the grid is at a high level; the NMOS is turned on when the gate is high, and turned off when the gate is low.

Wherein the coupling may comprise: the two ends are in direct physical contact or are connected indirectly (such as by a signal line). The coupling manner between the two ends is not limited in the embodiments of the present disclosure.

Fig. 1 is a schematic diagram of a charge status indicator circuit according to an embodiment of the disclosure. As shown in fig. 1, the charge state indicator circuit includes a first control branch circuit 10, a second control branch circuit 20, and an indicator element 30.

The first control branch circuit 10 is coupled to the charge state terminal, the reference voltage terminal CV, the input voltage terminal VIN and the first node N1 of the charging chip 40, respectively. The first control branch circuit 10 is configured to control the first node N1 to be coupled with the input voltage terminal VIN based on the charging normal signal output from the charging state terminal, so as to provide a first preset voltage to the first node N1. The second control branch circuit 20 is coupled to the first node N1, the positive pole Vbat of a battery (not shown), the input voltage terminal VIN, and the second node N2, respectively. The second control branch circuit 20 is configured to control the second node N2 to be coupled with the input voltage terminal VIN to provide the second preset voltage to the second node N2 when the first node N1 is a first preset voltage and the positive voltage Vbat of the battery is not greater than the cut-off voltage V _L.

The cut-off voltage V _L is the minimum voltage that the electronic device using the battery can start. When the positive voltage of the battery is greater than or equal to the cut-off voltage, the electronic equipment can be started, and when the positive voltage of the battery is less than the cut-off voltage, the electronic equipment cannot be started or started. When the battery of the electronic device is overdischarged, the positive Vbat voltage of the battery is less than the cut-off voltage, i.e. the positive Vbat voltage of the battery is less than the cut-off voltage V _L. At this time, the battery needs to be charged, when the positive voltage of the battery does not reach the cut-off voltage V _L in the charging process, the electronic device cannot be started or started, and when the charging is performed so that the positive voltage of the battery reaches the cut-off voltage V _L, the electronic device can be started or started.

The prompting element 30 is coupled to the second node N2 and the first ground GND1, respectively, and is configured to generate a predetermined prompting message at a second predetermined voltage of the second node N2. When the second node N2 is provided with the second preset voltage, the prompting element 30 is located in a loop between the second preset voltage and the first ground GND1, and the prompting element 30 works to generate the preset prompting information.

The charging chip 40 is used to manage the charging of the battery, for example, to control the current and/or voltage of the battery charging after the battery is overdischarged. In the example of the present disclosure, the charging chip 40 is further configured to output a charging normal signal at a charging state terminal of the charging chip 40 when the battery is charged normally.

Illustratively, when the electronic device is malfunctioning or damaged, the battery is charged abnormally, and the charge state terminal of the charging chip 40 outputs a charge abnormal signal or no signal is output. That is, in the abnormal state of charge of the battery, the state-of-charge terminal outputs a charge abnormality signal, and the first node N1 is disconnected from the input voltage terminal VIN based on the charge abnormality signal. That is, based on the abnormal charging signal, the first node N1 cannot be coupled to the input voltage terminal VIN through the first control branch circuit 10, the first predetermined voltage cannot be provided to the first node N1, and further, the second node N2 is disconnected from the input voltage terminal VIN, so that the prompting element 30 cannot generate the predetermined prompting information.

According to the technical scheme of the embodiment of the disclosure, after the battery is overdischarged, that is, the battery is charged when the voltage of the positive electrode Vbat of the battery is smaller than the cut-off voltage V _L, when the battery is normally charged, the charging state end of the charging chip 40 outputs a charging normal signal, and the first control branch circuit 10 controls the first node N1 to be coupled with the input voltage end VIN based on the charging normal signal so as to provide a first preset voltage for the first node N1; the second control branch circuit 20 controls the second node N2 to be coupled with the input voltage terminal VIN and provides the second node N2 with a second preset voltage when the first node N1 is a first preset voltage and the voltage of the positive electrode Vbat of the battery is not greater than the cut-off voltage; the prompting element 30 generates a preset prompting message at a second preset voltage. The user can judge that the battery is normally charged according to the received preset prompt information. When the positive voltage of the battery reaches the cut-off voltage V _L after the battery is charged for a period of time, that is, the positive voltage of the battery is greater than or equal to the cut-off voltage V _L, the prompting element 30 stops sending the prompting information.

The battery is charged after overdischarging, and when the battery is in an abnormal charge state, the charge state end outputs a charge abnormality signal, and the prompting element 30 does not generate preset prompting information. When the electronic device cannot be turned on and the prompting element 20 does not generate the preset prompting information, the user can judge that the electronic device is faulty or damaged so as to perform maintenance in time.

In the charge state prompting circuit of the embodiment of the disclosure, when the battery of the electronic device is overdischarged, and the electronic device is charged, although the electronic device cannot be started or started, a user can judge that the electronic device is normally charged according to preset prompting information sent by the prompting element 30; when the electronic device cannot be started or activated and the prompting element 30 does not send out the preset prompting information, the electronic device is used for judging that the electronic device is damaged and needs to be maintained. The state of the electronic equipment can be timely judged by the user through the state of the prompting element, the situation that the user waits for a long time to judge whether the electronic equipment is charged or damaged is avoided, convenience is provided for the user, and the satisfaction degree of the user is improved.

It should be noted that, in the present disclosure, when the voltage of the positive electrode Vbat of the battery is equal to the cut-off voltage V _L, the second control branch circuit 20 may be set to control the second node N2 to be coupled to the input voltage terminal VIN or disconnect the second node N2 from the input voltage terminal VIN according to the need. The voltage of the positive electrode Vbat of the battery equal to the cutoff voltage V _L should not be construed as limiting the present disclosure.

For example, the reminder element 30 may include an indicator light, for example, the preset reminder information may light the indicator light. For example, when the battery is charged after overdischarging, the indicator lamp is turned on at a second preset voltage, indicating that the battery is normally charged; when the indicator light is not lighted, the electronic equipment is in fault or damaged.

In other embodiments, the prompting element 30 may include a sound element, for example, the preset prompting message may sound for the sound element. For example, when the battery is charged after overdischarge, and the sound element emits a preset sound under a second preset voltage, the battery is judged to be normally charged; and when the sound original does not emit preset sound, judging that the electronic equipment is faulty or damaged.

Fig. 2 is a schematic diagram of a state of charge indicator circuit according to another embodiment of the disclosure, and fig. 3 is a schematic diagram of a state of charge indicator circuit according to another embodiment of the disclosure. As shown in fig. 2 and 3, the second control branch circuit 20 may include a first switching branch circuit 21 and a second switching branch circuit 22.

The first switching subcircuit 21 is coupled with the first node N1, the positive pole Vbat of the battery and the third node N3, respectively. The first switch subcircuit 21 is configured to turn on if the first node N1 is a first preset voltage and the positive pole Vbat voltage of the battery is not greater than the off voltage, such that the third node N3 is coupled with the positive pole Vbat of the battery.

The second switch branch circuit 22 is coupled to the third node N3, the input voltage terminal VIN, and the second node N2, respectively. The second switch subcircuit 22 is configured to conduct with the third node N3 coupled to the positive pole Vbat of the battery, such that the second node N2 is coupled to the input voltage terminal VIN.

For example, in the case where the first node N1 is a first preset voltage and the positive electrode Vbat voltage of the battery is not greater than the off voltage, the first switch branch circuit 21 is turned on, and the third node N3 is coupled to the positive electrode Vbat of the battery. After the third node N3 is coupled to the positive electrode Vbat of the battery, the second switch branch circuit 22 is turned on, the second node N2 is coupled to the input voltage terminal VIN, a second preset voltage is provided to the second node N2, and the prompting element 30 generates a preset prompting message.

When the positive electrode Vbat voltage of the battery is greater than the off-voltage, the first switching branch circuit 21 is turned off, the second switching branch circuit 22 is turned off, and the second node N2 is disconnected from the input voltage terminal VIN. Therefore, the second predetermined voltage cannot be provided to the second node N2, and the prompting element 30 cannot generate the predetermined prompting message.

Setting the second control branch circuit 20 to include the first switch branch circuit 21 and the second switch branch circuit 22 achieves that when the positive pole Vbat voltage of the battery is not greater than the off voltage, a second preset voltage is provided to the second node N2, so that the prompting element 30 generates preset prompting information; when the voltage of the positive electrode Vbat of the battery is greater than the cut-off voltage, the second node N2 is disconnected from the input voltage terminal VIN, and the prompting element 30 cannot generate the preset prompting information. Such a second control branch circuit 20 can not only fulfill the required functions but also be of simple construction.

In other embodiments, the second control branch circuit 20 may be provided in other configurations capable of performing its functions, as long as the functions of the second control branch circuit 20 are all capable of being performed.

In one embodiment, the second switch branch circuit 22 may include a first MOS transistor M1, where a gate of the first MOS transistor M1 is coupled to the third node N3, a first pole of the first MOS transistor M1 is coupled to the input voltage terminal VIN, and a second pole of the first MOS transistor M1 is coupled to the second node N2. One of the first pole and the second pole of the first MOS transistor M1 may be a source, and the other may be a drain.

In the case that the third node N3 is coupled to the positive electrode Vbat of the battery, the third node N3 may control the first MOS transistor M1 to be turned on, so that the second node N2 is coupled to the input voltage terminal VIN.

The function of the second switch branch circuit 22 can be conveniently realized by using the MOS tube, and the circuit can be simplified.

Illustratively, the first MOS transistor M1 may be a PMOS transistor, the first pole of the first MOS transistor M1 may be a source of the PMOS transistor, and the second pole of the first MOS transistor M1 may be a drain of the PMOS transistor.

When the battery overdischarge for some reason causes the positive Vbat voltage of the battery to be lower than the cutoff voltage, the protection circuit inside the battery makes the battery no longer discharge to the outside, and the battery is not discharged to the outside again until the positive Vbat voltage returns to be higher than the cutoff voltage. In some examples, the battery may be a lithium battery such as a lithium cobalt oxide battery, a ternary lithium battery, a lithium iron phosphate battery, or a polymer lithium battery, among others. It should be understood that batteries made of different materials may have different cutoff voltages, which is not limiting of the present disclosure.

When the first switch subcircuit 21 is turned on, the third node N3 is coupled with the positive pole Vbat of the battery, so that the voltage of the third node N3 is almost equal to the positive pole Vbat voltage of the battery. Therefore, the second switch branch circuit 22 includes the PMOS transistor, so that the PMOS transistor can be more easily turned on under the control of the voltage of the third node N3, and the structure of the first switch branch circuit 21 can be simplified.

When the first MOS transistor M1 includes a PMOS transistor, a difference between the voltage of the third node N3 (and the voltage of the gate of the first MOS transistor M1) and the voltage of the first pole of the first MOS transistor M1 is smaller than the threshold voltage of the first MOS transistor M1. Thus, the conduction of the source electrode and the drain electrode of the first MOS tube M1 can be realized.

When the first switch subcircuit 21 is turned on, the voltage of the third node N3 is almost equal to the positive pole Vbat voltage of the battery. In order for the presentation element 30 to generate the preset presentation information, the positive pole Vbat voltage of the battery is not greater than the off-voltage, that is, the positive pole Vbat voltage of the battery is less than or equal to the off-voltage. In order to realize the conduction of the source and the drain of the first MOS transistor M1, it is required to satisfy that the difference between the voltage of the third node N3 and the voltage of the first pole of the first MOS transistor M1 is smaller than the threshold voltage of the first MOS transistor M1. The maximum voltage of the third node N3 is the off voltage V _L, the voltage V _s of the first pole of the first MOS transistor M1, and the threshold voltage V _th1 of the first MOS transistor M1, then V _L-V_s<V_th1 needs to be satisfied when the first MOS is turned on. Therefore, a suitable voltage value of the input voltage terminal VIN and the first MOS transistor M1 can be selected according to V _L-V_s<V_th1.

As shown in fig. 2, a first resistor R1 may be connected between the gate and the first pole of the first MOS transistor M1, where the first resistor R1 is used to make the gate and the first pole of the first MOS transistor M1 have the same potential when the first switch branch circuit 21 is turned off.

When the first switch branch circuit 21 is turned off, the third node N3 is in a floating state, and the voltage value of the third node N3 is unstable. The first resistor R1 is connected between the gate and the first pole of the first MOS transistor M1, so that, when the first switch branch circuit 21 is turned off, the potential of the gate of the first MOS transistor M1 is the same as the potential of the first pole, that is, the voltage difference between the gate voltage and the first pole is 0, the first MOS transistor M1 does not satisfy the on condition, and it can be ensured that the first MOS transistor M1 is turned off. Thus, the false operation of the prompting element 30 can be prevented, and the accuracy of the prompting information of the prompting element 30 is ensured.

The resistance value of the first resistor element R1 may be selected such that, in the case where the first switch branch circuit 21 is turned off, the potential of the gate of the first MOS transistor M1 is the same as the potential of the first pole, ensuring the turn-off of the first MOS transistor M1; when the first switch branch circuit 21 is turned on, the third node N3 is coupled to the positive electrode Vbat of the battery, and the first MOS transistor M1 is turned on under the control of the third node N3.

In one embodiment, as shown in fig. 2, the first switch branch circuit 21 may include a first triode T1, a base (e.g., b-pole) of the first triode T1 may be coupled to the first node N1, an emitter (e.g., e-pole) of the first triode T1 may be coupled to the positive electrode Vbat of the battery, and a collector (e.g., c-pole) of the first triode T1 may be coupled to the third node N3. The voltage V _N1 at the first node, i.e., the first predetermined voltage, is equal to the sum of the off voltage V _L and the threshold voltage V _th2 of the first transistor T1, i.e.,

V _N1＝V_L+ V_th2 formula (1)

The threshold voltage V _th2 of the first transistor T1 is the minimum voltage between the base and the emitter when the first transistor T1 is turned on. In this way, when the voltage Vbat of the positive electrode of the battery is less than or equal to the off voltage V _L, the first transistor T1 is turned on, so that not only the function of the first switch branch circuit 21 can be realized, but also the circuit structure is simple.

The first transistor T1 may be an NPN transistor, for example.

As shown in fig. 2, a fifth resistance element R5 may be connected between the third node N3 and the collector of the first transistor T1, and a specific resistance value of the fifth resistance element R5 may be set as needed.

A seventh resistor R7 connected in series with the prompting element 30 may also be disposed between the second node N2 and the first ground GND1, so as to limit the current of the loop in which the prompting element 30 is located, and a specific resistance value of the seventh resistor R7 may be set as required.

In one embodiment, as shown in fig. 2 and 3, the first control branch circuit 10 may include a third switching branch circuit 11 and a fourth switching branch circuit 12.

The third switch branch circuit 11 is coupled to the charge state terminal of the charging chip 40, the reference voltage terminal CV and the fourth node N4, respectively. The third switch branch circuit 11 is configured to be turned on in a case where the charge state terminal outputs the charge normal signal, so that the fourth node N4 is coupled with the reference voltage terminal CV. For example, when the charging state terminal of the charging chip 40 outputs the charging normal signal, the third switch branch circuit 11 is turned on, and the fourth node N4 is coupled to the reference voltage terminal CV. When the charge state terminal outputs the charge abnormality signal, the third switch branch circuit 11 is turned off, and the fourth node N4 is disconnected from the reference voltage terminal CV.

The fourth switch branch circuit 12 is coupled to the fourth node N4, the input voltage terminal VIN and the first node N1, respectively. The fourth switch branch circuit 12 is configured to be turned on when the fourth node N4 is coupled to the reference voltage terminal CV, so that the first node N1 is coupled to the input voltage terminal VIN. In the case that the fourth node N4 is coupled to the reference voltage terminal CV, the fourth switching branch circuit 12 is turned on, and the first node N1 is coupled to the input voltage terminal VIN, so as to provide the first node N1 with the first preset voltage.

The first control branch circuit 10 is provided to include the third switching branch circuit 11 and the fourth switching branch circuit 12, so that not only the function of the first control branch circuit 10 can be realized, but also the structure is simple.

In other embodiments, the first control branch circuit 10 may be provided in other structures capable of performing its functions, as long as the functions of the first control branch circuit 10 are all capable of being performed.

As shown in fig. 2 and 3, a second resistor R2 is connected between the input voltage terminal VIN and the fourth switch branch circuit 12, and a third resistor R3 is connected between the first node N1 and the third ground GND 3. With this configuration, a suitable voltage value of the first node N1 can be obtained by selecting a suitable resistance value of the second resistance element R2 and the third resistance element R3.

The input voltage terminal VIN, the second resistor element R2, the fourth switch branch circuit 12, the third resistor element R3, and the third ground GND3 form a loop. The voltage V _N1 of the first node N1 satisfies:

the first switch subcircuit 21 may include a first transistor T1, the first node N1 being coupled to the base of the first transistor T1, V _N1 = Vb, such that the following relationship is satisfied:

Wherein V1 is the voltage of the input voltage terminal VIN, vb is the voltage of the base of the first triode T1, R2 is the resistance of the second resistive element R2, R3 is the resistance of the third resistive element R3, and Vb is the sum of the cut-off voltage and the threshold voltage of the first triode T1.

Thus, according to the formula (1) and the formula (3), it is possible to obtain

After V1, V _L, and V _th2 are determined, the resistance values of the second resistive element R2 and the third resistive element R3 may be selected appropriately according to the above formula (4).

As shown in fig. 2, the third switch branch circuit 11 may include a second transistor T2, a base of the second transistor T2 is coupled to the charge state terminal of the charging chip 40, an emitter of the second transistor T2 is coupled to the reference voltage terminal CV, and a collector of the second transistor T2 is coupled to the fourth node N4.

In one embodiment, the fourth switching branch circuit 12 may include a second MOS transistor M2. The gate of the second MOS transistor M2 is coupled to the fourth node N4, the first pole of the second MOS transistor M2 is coupled to the input voltage terminal VIN, and the second pole of the second MOS transistor M2 is coupled to the first node N1. Illustratively, the second MOS transistor M2 may include a PMOS transistor.

In an embodiment of the disclosure, as shown in fig. 2, an emitter of the second transistor T2 is coupled to the reference voltage terminal CV, the reference voltage terminal CV may be the second ground GND2, so that the second transistor T2 selects an NPN transistor, and correspondingly, the second MOS transistor M2 in the fourth switching branch circuit 12 may select a PMOS transistor.

In the embodiment shown in fig. 2, the first pole of the second MOS transistor M2 may be a source, and the second pole of the second MOS transistor M2 may be a drain.

In other embodiments, the emitter of the second transistor T2 may be coupled to a forward voltage terminal, the second transistor T2 may be a PNP transistor, and the second MOS transistor M2 may be a suitable NMOS transistor, which may also implement a corresponding function. For example, in the embodiment shown in fig. 3, the reference voltage terminal CV may be the first voltage terminal VCC1, and the first voltage terminal VCC1 may provide a high level voltage. And, the second transistor T2 is selected as a PNP transistor, and correspondingly, the second MOS transistor M2 in the fourth switching branch circuit 12 may be selected as an NMOS transistor. It can be understood that the normal charging signal output by the charging IC is a low level signal, which causes the PNP transistor T2 to be turned on, the first voltage terminal VCC1 can apply a high level voltage to the gate of the second MOS transistor M2, and the difference between the high level voltage and the input voltage V1 is greater than the threshold voltage of the second MOS transistor M2, which causes the second MOS transistor M2 to be turned on when the gate of the second MOS transistor M2 is applied with the high level voltage.

In the embodiment shown in fig. 3, the first pole of the second MOS transistor M2 may be a drain, and the second pole of the second MOS transistor M2 may be a source.

In one embodiment, as shown in fig. 2, a fourth resistor R4 is connected between the gate and the first pole of the second MOS transistor M2, and the fourth resistor R4 is used to make the gate and the first pole of the second MOS transistor M2 have the same potential when the third switch branch circuit 11 is turned off.

When the third switch branch circuit 11 is turned off, the fourth node N4 is in a floating state, and the voltage value of the fourth node N4 is unstable. A fourth resistor element R4 is connected between the gate and the first pole of the second MOS transistor M2, and then, under the condition that the third switch branch circuit 11 is turned off, the potential of the gate of the second MOS transistor M2 is the same as the potential of the first pole, that is, the voltage difference between the gate voltage and the first pole is 0, the second MOS transistor M2 does not meet the conduction condition, and it can be ensured that the second MOS transistor M2 is turned off. Thus, the second MOS transistor M2 can be prevented from misoperation during abnormal charging, and the accuracy of the prompt information of the prompt element 30 is ensured.

The resistance value of the fourth resistor element R4 may be selected so that, in the case of the third switch branch circuit 11 being turned off, the potential of the gate of the second MOS transistor M2 is the same as the potential of the first pole, ensuring the turn-off of the second MOS transistor M2; in addition, when the third switch branch circuit 11 is turned on, the fourth node N4 is coupled to the reference voltage terminal CV, and the second MOS transistor M2 is turned on under the control of the fourth node N4.

For example, as shown in fig. 2 or 3, a sixth resistive element R6 may be disposed between the fourth node N4 and the collector of the second transistor T2, and a specific resistance value of the sixth resistive element R6 may be set as needed.

As shown in fig. 2, an eighth resistor R8 may be disposed at the base of the second transistor T2 as a pull-down resistor, where one end of the eighth resistor R8 is coupled to the base of the second transistor T2 and the other end is coupled to the fourth ground GND 4. The specific resistance value of the eighth resistive element R8 is set as needed.

It should be noted that the reference to multiple references described herein, such as a first reference, a second reference, a third reference, and a fourth reference, or other reference, is not meant to be limiting of the reference ground connection points and reference potentials herein, and one skilled in the art may set a single reference as desired, or multiple references as described herein.

As shown in fig. 3, when the second transistor is selected as a PNP transistor and the second MOS transistor is selected as an NMOS transistor, the eighth resistive element R8 is configured as a pull-up resistor, and one end of the eighth resistive element R8 is coupled to the base of the second transistor T2, and the other end is coupled to the second voltage terminal VCC 2. The specific resistance value of the eighth resistive element R8 is set as needed.

For example, the charge state indicator circuit may further include a diode D1, an anode of the diode D1 may be coupled to the input voltage terminal VIN, and a cathode of the diode D1 may be coupled to the first pole of the first MOS transistor M1.

It should be noted that, fig. 2 shows exemplary structures of the first switch branch circuit 21, the second switch branch circuit 22, the third switch branch circuit 11, and the fourth switch branch circuit 12, and those skilled in the art will understand that the first switch branch circuit 21, the second switch branch circuit 22, the third switch branch circuit 11, and the fourth switch branch circuit 12 are not limited to the structures shown in fig. 2, as long as the functions thereof can be realized.

The following describes in detail the operation principle of the charge state indicator circuit according to the embodiment of the present disclosure with reference to fig. 2.

When the battery is overdischarged (the positive electrode Vbat of the battery is smaller than the cutoff voltage V _L), the battery is charged, and the voltage at the input voltage terminal VIN (which may also be called a charging voltage terminal) is V1.

When the charge state terminal of the charging chip outputs the charge normal signal, for example, the charge normal signal is a high level signal, the base of the second triode T2 is high level, the second triode T2 is turned on, so that the fourth node N4 is coupled to the reference voltage terminal CV, that is, the gate of the second MOS transistor M2 is coupled to the reference voltage terminal CV through the sixth resistor element R6 and the second triode T2. At this time, the gate voltage of the second MOS transistor M2 may be considered as 0, and the voltage of the first pole (source) of the second MOS transistor M2 may be considered as V1, so vgs= -V1 of the second MOS transistor M2 satisfies Vgs < V _th4,V_th4 to be the threshold voltage of the second MOS transistor, the second MOS transistor M2 is turned on, the first node N1 is coupled to the input voltage terminal VIN through the second MOS transistor M2, a first preset voltage is provided to the first node N1, the first preset voltage is the voltage of the base of the first triode T1, and the above formula (3) is satisfied.

In order to make the first triode T1 conductive, it is required to satisfy Vb-Vbat.gtoreq.V _th2 >0, and further satisfy the above formula (4).

The voltage drop of the diode D1 may be set to Vd, and the voltage vs=v1-Vd of the first pole of the first MOS transistor M1 after the input voltage VIN passes through the diode D1. After the first transistor T1 is turned on, the third node N3 is coupled to the positive electrode of the battery through the fifth resistor element R5 and the first transistor T1, and the voltage of the third node N3, that is, the gate voltage vg=vbat of the first MOS transistor M1 can be considered. At this time, in order to turn on the first MOS transistor M1, vbat-Vs < V _th1, i.e., vbat- (V1-Vd) < V _th1, further, it can be derived that

V _th1>V_L - (V1-Vd), equation (5)

Wherein V _th1 is the threshold voltage of the first MOS transistor.

The first MOS transistor can be selected according to the formula (5), so that the first MOS transistor can be fully turned on to light the indicator lamp D2 when the battery is normally charged.

When the electronic device is charged after overdischarge, the electronic device cannot be turned on but the indicator lamp D2 is turned on, and the user can determine that the electronic device is being charged with a low battery.

It can be appreciated that the frequency of the charging normal signal output by the charging IC during normal charging may be set as required, for example, it may be 10Hz, 5Hz, or other higher or lower frequencies, which makes the indicator light D2 flash based on the frequency of the charging normal signal, so that the reminding is more obvious.

In the charging process, when the electronic device fails or is damaged, the charging state end of the charging chip outputs a charging abnormal signal, for example, the charging abnormal signal is a low level signal, at this time, the base electrode of the second triode T2 is at a low level, the second triode T2 is turned off, no current flows through the sixth resistor R6, under the action of the fourth resistor R4, the voltage between the gate electrode and the source electrode of the second MOS tube M2 is consistent, the second MOS tube M2 does not meet the conducting condition, the second MOS tube M2 is turned off, the first node N1 is disconnected from the input voltage end VIN, the first triode T1 is turned off, no current flows through the fifth resistor R5, under the action of the first resistor R1, the voltage between the gate electrode and the source electrode of the first MOS tube M1 is consistent, the first MOS tube M1 is turned off, and the indicator lamp D2 is in an off state. At this time, the electronic device cannot be turned on or started, and the indicator light D2 is not turned on, so that the user can determine that the electronic device is faulty or damaged, and repair of the electronic device is required.

In the embodiment of fig. 2, the charging normal signal output by the charging chip is a high level signal, and the charging abnormal signal is a low level signal. In the embodiment of fig. 3, the charging normal signal output by the charging chip may be set to a low level signal, and the charging abnormal signal may be set to a high level signal.

The disclosed embodiments also provide an electronic device including a charging chip 40, a battery, and a state of charge indicator circuit in any of the disclosed embodiments.

The electronic device may be charged, and the electronic device may include at least one of a mobile phone, a tablet computer, a notebook computer, a vehicle-mounted terminal device, and the like.

In the electronic device according to the embodiment of the present disclosure, due to the adoption of the charge state prompting circuit according to the embodiment of the present disclosure, when the battery is charged after overdischarge, if the electronic device cannot be started, the prompting element 30 generates a preset prompting message, and a user can determine that the electronic device is not damaged through the preset prompting message; if the electronic device cannot be started and the prompt element 30 does not generate the preset prompt information, the user can judge that the electronic device has faults or damages, so that the user can maintain the electronic device in time, the situation that the user waits for a long time to judge whether the electronic device is being charged or damaged is avoided, convenience is provided for the user, and the satisfaction degree of the user is improved.

In this disclosure, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present disclosure, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present disclosure, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; the device can be mechanically connected, electrically connected and communicated; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this disclosure will be understood by those of ordinary skill in the art as the case may be.

The above disclosure provides many different embodiments or examples for implementing different structures of the disclosure. The components and arrangements of specific examples are described above in order to simplify the present disclosure. Of course, they are merely examples and are not intended to limit the present disclosure. Furthermore, the present disclosure may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed.

The above is merely a specific embodiment of the disclosure, but the protection scope of the disclosure is not limited thereto, and any person skilled in the art can easily think of various changes or substitutions within the technical scope of the disclosure, which should be covered in the protection scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A state of charge prompting circuit, comprising:

The first control branch circuit is respectively coupled with a charging state end, a reference voltage end, an input voltage end and a first node of the charging chip and is configured to control the first node to be coupled with the input voltage end based on a charging normal signal output by the charging state end so as to provide a first preset voltage for the first node;

A second control branch circuit coupled to the first node, the positive electrode of the battery, the input voltage terminal, and a second node, respectively, and configured to control the second node to be coupled to the input voltage terminal to provide a second preset voltage to the second node, in a case where the first node is a first preset voltage and the positive electrode voltage of the battery is not greater than a cut-off voltage, the cut-off voltage being a minimum voltage that an electronic device using the battery can start;

and the prompting element is coupled with the second node and the first reference ground respectively and is configured to generate preset prompting information under a second preset voltage of the second node.

2. The circuit of claim 1, wherein the second control branch circuit comprises:

A first switch branch circuit coupled to the first node, the positive electrode of the battery, and a third node, respectively, and configured to be turned on when the first node is a first preset voltage and the positive electrode voltage of the battery is not greater than a cut-off voltage, such that the third node is coupled to the positive electrode of the battery;

3. The circuit of claim 2, wherein the first switch branch circuit is turned off and the second node is disconnected from the input voltage terminal in the case that the positive voltage of the battery is greater than the off voltage.

4. The circuit of claim 2, wherein the second switch subcircuit comprises a first MOS transistor having a gate coupled to the third node, a first pole coupled to the input voltage terminal, and a second pole coupled to the second node.

5. The circuit of claim 4, wherein a first resistive element is connected between the gate and the first pole of the first MOS transistor, the first resistive element being configured to make the gate and the first pole of the first MOS transistor at the same potential when the first switch branch circuit is turned off.

6. The circuit of claim 4, wherein a difference between a voltage of the third node and a voltage of the first pole of the first MOS transistor is less than a threshold voltage of the first MOS transistor.

7. The circuit of claim 2, wherein the first switching subcircuit comprises a first transistor having a base coupled to the first node, an emitter coupled to the positive electrode of the battery, and a collector coupled to the third node;

The first preset voltage is equal to the sum of the cut-off voltage and the threshold voltage of the first triode, and the threshold voltage of the first triode is the minimum voltage between the base electrode and the emitter electrode, which enables the first triode to be conducted.

8. The circuit of any of claims 1-7, wherein the first control branch circuit comprises:

A third switch branch circuit respectively coupled with a charging state end of the charging chip, the reference voltage end and a fourth node, and configured to be turned on under the condition that the charging state end outputs a charging normal signal, so that the fourth node is coupled with the reference voltage end;

And a fourth switching branch circuit coupled to the fourth node, the input voltage terminal, and the first node, respectively, and configured to be turned on when the fourth node is coupled to the reference voltage terminal, so that the first node is coupled to the input voltage terminal.

9. The circuit of claim 8, wherein a second resistive element is connected between the input voltage terminal and the fourth switching branch circuit, a third resistive element is connected between the first node and a third reference ground, and the following relationship is satisfied where the first switching branch circuit includes a first transistor and the first node is coupled to a base of the first transistor:

10. The circuit of claim 8, wherein the fourth switching branch circuit comprises a second MOS transistor having a gate coupled to the fourth node, a first pole coupled to the input voltage terminal, and a second pole coupled to the first node.

11. The circuit of claim 10, wherein a fourth resistive element is connected between the gate and the first pole of the second MOS transistor, the fourth resistive element being configured to make the gate and the first pole of the second MOS transistor at the same potential when the third switch branch circuit is turned off.

12. The circuit of claim 8, wherein the third switching subcircuit comprises a second transistor having a base coupled to a state of charge terminal of the charging chip, an emitter coupled to the reference voltage terminal, and a collector coupled to the fourth node.

13. The circuit of claim 1, wherein the state of charge terminal outputs a charge anomaly signal upon an abnormal state of charge of the battery, the first node being disconnected from the input voltage terminal based on the charge anomaly signal.

14. An electronic device comprising a charging chip, a battery, and a state of charge indicator circuit as claimed in any one of claims 1 to 13.